Markers to differentiate between Kaposi's sarcoma and tuberculous pleural effusions in HIV-positive patients

Int J Tuberc Lung Dis. 2015 Feb;19(2):144-50. doi: 10.5588/ijtld.14.0289.


Background: Kaposi's sarcoma (KS) and tuberculosis (TB) commonly cause pleural effusions in high human immunodeficiency virus (HIV) burden resource-limited countries. Differentiating between them is challenging, as pleural biopsy and TB culture are rarely available.

Objectives: To identify markers to differentiate between TB effusions and KS effusions in HIV-positive patients, and to compare liquid culture and Xpert MTB/RIF in pleural fluid.

Methods: Fifty HIV-positive patients with pleural effusions recruited in Malawi underwent pleural ultrasound and aspiration. Fluid visual inspection, cell count, bacterial culture, glucose/protein, solid and liquid TB culture and Xpert were performed.

Results: The mean age of the patients was 32 years; 30/50 (60%) were male and 29 (58%) had cutaneous/oral KS. Thirteen (26%) pleural fluid samples were liquid culture-positive for TB, while 9/13 (69%) were Xpert-positive. Three (10.3%) KS patients had culture-positive TB effusions; 17 (58.6%) had KS effusions. The relative risk of TB in KS patients increased with limited KS, loculated fluid and low glucose. Eleven (52.3%) non-KS patients had culture-positive TB effusions associated with male sex, straw-coloured fluid and fibrin stranding on ultrasound.

Conclusions: KS patients were most likely to have KS effusion, but TB should be considered. Most non-KS patients had TB, supporting the use of World Health Organization guidelines. Xpert identified two thirds of liquid culture-positive results.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Female
  • HIV Infections / complications*
  • Humans
  • Malawi
  • Male
  • Middle Aged
  • Pleural Effusion / diagnosis*
  • Pleural Effusion / microbiology
  • Polymerase Chain Reaction / methods
  • Prospective Studies
  • Sarcoma, Kaposi / diagnosis*
  • Sarcoma, Kaposi / virology
  • Tuberculosis, Pleural / diagnosis*
  • Tuberculosis, Pleural / microbiology
  • Young Adult